On the stroke of midnight on New Year's Eve, while half the country was asleep and the other half might just as well have been, Britain could finally claim to be a fully paid-up member of the world's democracies. After years of campaigning by pressure groups - not to mention governmental procrastination - the UK joined more than 100 other countries in allowing public access to some official records as its new Freedom of Information Act came into effect.

The Campaign for Freedom of Information had been working towards this moment for more than 20 years, and its director, Maurice Frankel, was understandably upbeat about the act. "The new rights will help people ensure they are being treated fairly, learn whether they are being exposed to hazards, check that public authorities are doing their job and give people a better chance of influencing decisions," he said. "They should also lead to more honesty in government. Giving the public the right to see the documents will make it harder for authorities to conceal substandard performance or get away with spin or misleading accounts of what they are doing."

There were some caveats, though. In the run-up to January 1 there were fears that government departments were indulging in some ruthless housekeeping by shredding awkward documents, which only exacerbated existing concerns that ministers were going to extend the right to non-disclosure from the legitimate aims of protecting national security, law enforcement and international relations to include protecting reputations and hiding cock-ups. "The legislation's most contentious feature is a ministerial veto, allowing cabinet ministers to override the Information Commissioner if he orders a government department to release information on public interest grounds," Frankel continued. "No one is putting any bets on ministers being able to resist its use where politically damaging information is at stake."

Discovering the really interesting information will largely depend on knowing what questions to ask. The general public might struggle here, but if anyone should know where the bodies are buried it's an academic. Peter Hennessy's postgraduate students have formed a Freedom of Information hit-squad to target documents from the late 70's - on the grounds that the government is likely to care less about their disclosure than about papers from more recent times - but it's fair to say there hasn't exactly been a stampede of researchers rushing to the post office to send off their requests to Whitehall. With more than four years to prepare for the implementation of the act, even the doziest researcher can hardly complain he or she was caught on the hop, so could it just be there may be not as much hidden treasure as one might imagine?

Anyone anticipating a similar deluge of information to that uncovered in the former Soviet bloc countries in the early 1990s is likely to be disappointed. For one thing, many records only ever existed in the minds of conspiracy theorists, and for another, the Major government had already released some 80,000 restricted cold war files in 1992 under the Waldegrave "open government" initiative. And the picture that emerged was not necessarily the one expected.

"The documents revealed a great deal about espionage in the cold war era, together with information on how and why the H-bomb was built," says Peter Hennessy, Attlee professor of contemporary history at Queen Mary College, University of London, who spent five years wading through the archive for his book, The Secret State. "But perhaps the most interesting aspect has been Britain's retaliation procedures in the event of nuclear war.

"The British went out of their way to avoid confrontation. The guardians of the secret state are often portrayed as gung-ho rightwingers, but that view is quite wrong. Here they are revealed as thoroughly British good chaps, practising self-restraint. They didn't want to follow the American McCarthyist route: rather they tried to preserve due process and civil liberties."

This is not something that could be said of the Blair government, with its indefinite imprisonment without trial for terrorist suspects and the planned introduction of ID cards. Campaigners for freedom of information - including this newspaper - have applied for the attorney general's opinion on the legality of the second Gulf war to be made public, but no one seriously expects the government to acquiesce on this or other sensitive issues.

Despite the trail of emails that have plagued the government - Jo Moore, the Butler inquiry and the Blunkett affair - many academics believe that governments are becoming increasingly wary of committing any evidence to paper or hard drive. "Most of the key discussions take place in informal meetings in Tony Blair's den before cabinet," says Anthony Seldon, headteacher of Brighton College and author of a bestselling biography of the prime minister. "All the important decisions on the Iraq war were taken in this way; cabinet merely rubber-stamped them. So even if the papers were released, they wouldn't tell us very much because they would be so bland as to be virtually worthless."

This may be less of an interference to scholarship than might be imagined. "Newspapers always make a big deal about information released under the 30-year rule," Seldon continues, "but the reality is that we rarely learn anything we didn't know already. All the important papers on Suez, the International Monetary Fund and the Falklands have just confirmed what we really knew already. This is useful for dotting the Is and crossing the Ts and for providing precise quotations, but it doesn't lead to a fundamental reassessment of our recent history."

Seldon maintains that interview technique is now more important for the modern historian than familiarity with the byways of the archives. "We live in a more confessional age," he says. "Politicians and civil servants may not want to be held to account by a written document, but they are still happy to confide in someone they trust. Not everyone is always happy with the way decisions are reached and so the truth has a way of leaking out. People are far more indiscreet these days, so government secrets tend to become public knowledge within days or weeks rather than months or years."

Greg Philo, director of the Glasgow Media Group at Glasgow University, confirms this trend. "People have realised how email has made it difficult to control the flow of information," he says, "so all the important evidence is now to be gained from conversations with the people involved. What we really need to know is not what decision was reached, as that is usually obvious, but who was paying for what and whose interests were being appeased, and this kind of information will never appear in the official records.

"We got an excellent insight into this when researching food scares prior to the BSE inquiry. Many scientists were bound by confidentiality clauses but said they had decided to no longer eat beef. This was before the sale of beef was banned, so we had a clear picture that something was wrong long before the government decided to act.

"Hard as they might try, governments can no longer totally control what information is made public. Everyone is much more cynical and disenchanted with the political process than they were 30 years ago, and the culture of deference and confidentiality has all but disappeared. When we first published our book Bad News, in 1976, everyone thought it was outrageous that we should be so critical of the BBC. Now everyone takes such comments for granted and the BBC has even asked us to help out with their own staff training."

Not that there aren't pieces of information that academics would dearly love to get their hands on. "For some years now, I've been trying to find out the government's plans for handling food insecurity during times of war," says Tim Lang, professor of food policy at City University. "Each time I've been gently rebuffed. I'm happy to have another go under the new act, but I'm not expecting a different outcome."

This isn't to say that Lang believes the new act to be worthless. For some years now he has been on the council for freedom of information and he welcomes any move towards a more open society. "Britain is the most secretive country alongside China and the former Soviet Union," he says. "So anything that helps you to keep tabs on the state has to be a step in the right direction. But I don't think the act will mark a quantum leap in openness."

In any case the act will be of little use to Lang in getting the information he really wants. "It might make the government more accountable," he says, "but in food policy, it's more often than not inside the large multinationals where the real evidence is to be found and the act has no powers over them. So the motives and reach of the big food companies are likely to remain secret."

Professor Hugh Pennington, chair of bacteriology at Aberdeen University and the man who has headed various government food inquiries, is also equivocal about the impact of the act. "Openness is always to be encouraged," he says, "but my own experience makes me wonder how much difference it will make. As far as the BSE inquiry was concerned, it would have been nice to have got an insight into the exact relationship between the scientists and the policy makers, because everything pointed to a complete breakdown, but I'm not sure what the paper evidence would have been.

"The real scandal is usually not to be found in somebody actively concealing information, but from a lack of activity. Stasis and inertia are the real cause of most cock-ups and, by definition, there is going to be a lack of a paper trail for researchers to find. I'm also concerned that governments might choose to flood the public with useless information in order to conceal one damaging fact. In some ways, it's comparable to the research assessment exercise (RAE); departments submit so many papers of varying worth that it's almost impossible for an assessor to read them all in the time available and rank them on their proper merit."

Any comparison to the RAE is likely to be the kiss of death for the act as far as most academics are concerned. In fact, you sense they would be amazed if anything of real importance came to light as a result of the act. "It's an important constitutional reform, one of the few radical acts of the current government," says Lang. "But my hunch is that no one will be losing much sleep over what may come out."

The devil's in the detail

The Freedom of Information act gives the public new rights to information held by government departments, parliament, local authorities, NHS bodies, schools, colleges, universities, the police, the armed forces, museums, quangos, regulators, publicly owned companies and the devolved assemblies. The courts, security and intelligence services are exempt. Under the Environmental Information Regulations, people will also have more rights to information on pollution, genetic modification, food contamination and other related issues.

If you want certain information you should:

1. Apply in writing or by fax or email to the authority which you think holds the information, addressing your request to the "Freedom of Information Officer" at the authority's address. Describe the information you want as specifically as possible. Requests that are too general or too sweeping may be refused.

2. Tell the authority you look forward to hearing from it "promptly" and in any case within 20 working days, as normally required under the FOI Act and EIRs. If you are applying for personal data about yourself, the authority has up to 40 days.

3. In most cases you won't have to pay for information, apart from copying and postage costs, provided your request isn't too sweeping. Note that: (a) under the UK FOI Act, an authority can refuse a request if finding and extracting the information will cost more than £450, equivalent to two and a half days' work at a set £25-an-hour rate. For government departments the limit is £600 or three and a half days' work; and (b) under the Scottish FOI Act the authority can't refuse a request unless it would cost more than £600 (nearly six days' work at £15 an hour). The first £100 of any costs are waived.

4. Authorities can withhold information under the UK FOI Act if disclosure would prejudice defence, international relations, law enforcement, commercial interests, the economy or collective cabinet responsibility or inhibit frank discussions by officials.

5. If you are unreasonably refused information or disagree with the fee, your first step should be to ask the authority to reconsider its decision. After that you can complain to the Information Commissioner. The Commissioner can order the authority to disclose information if it is not exempt or if disclosure is in the public interest. However, a ministerial veto allows ministers to overrule the Commissioner if he orders them to disclose information on public-interest grounds.